Page:The American Cyclopædia (1879) Volume XI.djvu/443

 METEOR 431 on the buildings, and other objects. On the same night in 1831 and in 1832, the same phe- nomenon reappeared in Europe and America. But the year 1833 is memorable for the most magnificent display on record. This was on the same night of November also, and was visible over all the United States, and over a part of Mexico and the West India islands. Together, with the smaller shooting stars, which fell like snow flakes and produced phos- phorescent lines along their course, there were intermingled large fire balls, which darted forth at intervals, describing in a few seconds an arc of 30 or 40. These left behind luminous trains, which remained in view several min- utes, and sometimes half an hour or more. One of them seen in North Carolina appeared of larger size and greater brilliancy than the moon. Some of the luminous bodies were of ir- regular form, and remained stationary for a con- siderable time, emitting streams of light. At Niagara the exhibition was especially brilliant, and probably no spectacle so terribly grand and sublime was ever before beheld by man as that of the firmament descending in fiery tor- rents over the dark and roaring cataract. It was observed that the lines of all the meteors if traced back converged in one quarter of the heavens, which was y Leonis Majoris; and this point accompanied the stars in their apparent motion westward, instead of moving with the earth toward the east. The source whence the meteors came was thus shown to be inde- pendent of the earth's rotation and exterior to our atmosphere. As computed by Prof. Deni- son Olmsted of New Haven, it could not have been less than 2,238 m. from the earth. Three successive annual returns of this phenomenon on the same night led astronomers on both sides of the Atlantic in the following years to watch for its recurrence; and displays more or less brilliant, but not by any means equal to that of 1833, were witnessed in different places in Europe or America every year till and in- cluding 1839. They were again observed on the night of Nov. 12-13, 1841 and 1846, and again in 1866 and every following year till 1871 inclusive. But it is not alone in November that periodic exhibitions of the fall of meteors have been observed. It is found that they often occur about the 10th or from the 9th to the 14th of August; and Humboldt named other periods that are likely to prove of the same interest, as about the 22d to the 25th of April, between the 6th and ^Lth of December, the 27th and 29th of November, and about the 17th of July. He noticed the singular coinci- dence which different observers have remarked in the great brilliancy of the aurora borealis during the fall of the meteors. Prof. Olmsted early suggested that the meteors probably emanate from a nebulous body, which re- volves around the sun in an elliptical orbit, the aphelion of which meets the orbit of the earth at the times of the annual exhibitions. The nebular character is inferred from the 549 VOL. xi. 28 fact that none of the meteors, though they fall toward the earth with prodigious velocity, ever reach it in a solid state, all being dissi- pated in the atmosphere, and no material sub- stance found to indicate their nature. Arago adopted a view similar to that of Olmsted. He suggests that the meteoric bodies may consti- tute a stream in the form of an annular zone, within which they pursue one common orbit; that there are several such streams, which intersect, each at its own period, the earth's orbit ; and that through each the myriads of small cosmical bodies are irregularly dispersed. But the demonstration of the real orbits pur- sued by these bodies (at least in the case of the more remarkable periodical showers) be- longs to the years following the display of Nov. 13-14, 1866. Prof. Newton of Yale col- lege had predicted the recurrence of a great display of November meteors, such as had been seen in the years 1799 and 1833, for the year 1866; and he even announced as the probable hour of the display early morning in America. He was within a few hours of the truth, the display occurring during the early morning in Europe, and closing before morn- ing began in America. European astronomers noted the point in the heavens whence the meteors seemed to radiate, not far from the star y Leonis, as in 1833. Then followed an inquiry into the orbit of the meteors. Prof. Newton had indicated five orbits as capable of explaining the recurrence of great displays about thrice in a century. Of these the three most probable were : first, a year and ^ part ; secondly, a year less ^ part ; and thirdly, 33J years. Prof. Newton considered the last named period improbable, because it implied an orbit extending beyond the orbit of the distant plan- et Uranus. He therefore regarded a period of rather more or rather less than a year as prob- ably the true period of these meteors. But just at this time a remarkable discovery was made by Schiaparelli of Italy. Noticing that the comet II., 1862, passed the earth's orbit nearly at the place she occupies on Aug. 10-11, he was led to inquire whether the path followed by the comet resembled that traversed by the August meteors, assuming that they have the same period of revolution as the comet (about 124 years). He found the agreement so close as to leave no doubt of the existence of a real association between the August meteors and the large comet of 1862. This will be seen from the following comparison : ELEMENTS. Comet of 1862. August meteors. 844-41' 137 27 66 25 0-9626 123-74 Eetrograde. 843 88' 188 16 64 3 0-9643 Eetrograde. Longitude of ascending node. . . Perihelion distance Period Astronomers therefore began to regard as not improbable the theory that the true period of the November meteors is about 33 years.